Measure all your ingredients before beginning and have them ready. This is very important.
In a deep 3 quart saucepan, pour the water, and then the sugar. Don’t stir it.
Bring the mixture to a boil over medium heat. If there’s sugar stuck on the sides of the pan, carefully brush it with a heat-resistant silicone brush dipped in a little water. Feel free to swirl the pan to give the mixture a stir, but when you set it back on the burner, brush the edges of the pan with water to dissolve the sugar crystals from the walls of the pot.
Once the sugar is completely dissolved and the mixture starts to bubble, you can increase the heat on the stove to medium–high, or you can leave it on medium. The only difference is that on medium, it will take longer for the mixture to caramelize.
Continue to boil the caramel until it turns amber in colour. As soon as the caramel has reached the desired colour, slide the pan off the heat, and turn the burner off.
Slowly and carefully drop in the cubed butter (it will bubble and erupt so be careful!). Pour in the cream, slowly and carefully.
When the bubbling has calmed down, begin to gently whisk the caramel until it is smooth and homogeneous.
Poor the salted caramel in a large jar and cover loosely. When the caramel has cooled to room temperature, you can tighten the lid and store it in the refrigerator. It will thicken as it cools.
Notes
I highly recommend watching the colour change closely to determine if your caramel has cooked enough, but if you want to check the temperature, aim for somewhere between 350°F and 360°F with a candy thermometer before adding the butter and cream.